This invention relates generally to friction clutches, and has particular reference to a novel clutch construction that permits variations in the release lever ratio without in any way changing the structure of the lever itself.
As is well known in the art, the free inner ends of the release levers of heavy duty vehicular clutches are either pushed or pulled by the release mechanism to move the clutch pressure plate out of engagement with the friction disc and thereby disengage the clutch. It is recognized also that it is desirable to vary the mechanical advantage exerted by the release levers on the clutch pressure plate according to the clutch construction. Thus, for example, it is desirable to provide a high mechanical advantage in single disc clutches because high spring forces are needed in such a clutch. On the other hand, in two disc clutches a lower mechanical advantage must be applied to allow increased retraction of the pressure plate for proper clutch disengagement.
Heretofore, different mechanical advantage requirements have resulted in the need for different release lever systems. This in turn has required clutch manufacturers to maintain two different kinds of tooling and separate parts inventories, all of which increases the cost of manufacture.